Today, the public has unprecedented access to the political decision-making process thanks to democratic norms, technological advancements in telecommunications, and archival capacities. Office-holders and prominent public figures are routinely placed under a social microscope, as their every move is dissected in an attempt to learn more about their character, intentions, and possibly their consequential decisions. However, students of ancient socio-political history do not benefit from similar levels of knowledge about the collective decision-making process, because of the nature of the extant evidence. Despite the centuries-old interest in the socio-political history of the Greco-Roman world, we have generally been limited to analyzing public decisions through the filter of historical hindsight, trying to dissect the oftentimes opaque and formulaic epigraphic voice of a seemingly confident and unified δῆμος. These limitations obstruct our efforts to gain insight into the tensions, intentions, and priorities that a collective decision-making body would have considered, which would in turn offer us a more in-depth understanding of ancient institutions and the social dynamics that governed them. In my dissertation, I look to bypass these historiographic obstacles by employing the concept of risk to ancient decision-making. To do so, I adopt Decision Theory to highlight the cognitive processes behind a community’s response to present and potential threats. I argue that ancient decision-makers understood risk as a deliberative craft – at times specifically referred-to as a τέχνη – that could be exercised to assess dangers, identify options, and decide on the response to a crisis. In the process, I explore the specific linguistic and cultural context that allowed ancient decision-makers to express and practice contingency planning and the quantification of uncertainty. With an added focus on epigraphic documents, I also highlight the importance of collective memory, cult, and psychology, in developing risk mitigating tools by fostering social cohesion to elicit a strong communal response to danger. My dissertation fills an important gap in Classical scholarship by providing the first study on the conceptualization of socio-political risk in antiquity. At the same time, it challenges sociological assumptions that the notion of risk is unsuited to the study of the ancient world. I thus argue against Ulrich Beck’s dominant position that only modern society can be thought of as a “risk society,” due to the advent of the systematic study of statistics in the 17th century. In the process, I show that Hellenistic decision-making enjoyed the same traits that have been identified as specific to modernity: namely, futurity, causality, and responsibility. The organization of the dissertation follows the cognitive process of risk-taking, to emphasize the systematic conceptualization of ancient risk as “deliberative expertise” during the Hellenistic period. Chapter 1 lays out the philological foundation of the project, by showing how risk was expressed through the ancient Greek language. I look at the intellectual engagement of Hellenistic historians with Aristotelian ideas, and I argue that risk management was understood as the conceptual intersection between deliberation and τέχνη. Chapters 2 and 3 tackle the matter of identifying and assessing risks. I point to an established network of communication and information-sharing, that allowed Hellenistic communities to remain vigilant and respond rapidly to sudden upheavals. Chapter 4 explores the temporal aspect of ancient risk management, which in turn allows us to gain more insight into how Hellenistic communities undertook contingency planning. The conceptual pairing of τύχη with καιρός illustrates the importance of “reading” the circumstances of a crisis, and identifying the opportune moment to respond to present and potential threats. Chapter 5 takes a longue durée approach to ancient socio-political risk, and looks at how historical precedents were employed by Hellenistic decision-makers to predict future outcomes in similar circumstances. I conclude that we can indeed refer to Hellenistic society as a “risk society.” At the same time, I highlight the continued dynamism and agency of the Greek polis in the post-Classical era, contradicting modern preconceptions of a general poliadic resignation to the post-Alexandrian realities. Moreover, we witness the workings of a society that is deeply conscious of futurity, as it constantly weighs short-term benefits against long-term developments. Finally, my conclusions render the Hellenistic oikoumenē more intelligible to modern audiences, as inter-disciplinary theoretical models allow us to replace schematic notions of antiquity with a complex portrait of socio-political realities. As in our own contemporary society, we witness the mechanics of an oikoumenē governed by numerous and sometimes conflicting intentions, inferences, estimations, speculations, as well as cultural contradictions.